ETHNIC-DIFFERENCES IN CYCLIC-AMP ACCUMULATION - EFFECT ON ALPHA-2, BETA-2, AND PROSTANOID RECEPTOR RESPONSES

Platelet α2- and lymphocyte β2-adrenergic receptor density and responsiveness and platelet responses to prostaglandin E2 (PGE2) were measured in black subjects and white subjects. Mean (±SEM) α-receptor density was greater in white subjects (248 ± 29 versus 392 ± 31 fmol/mg protein; p < 0.005), whereas β-receptor densities were similar (black subjects, 19.2 ± 2.2 fmol/mg protein; white subjects, 15.2 ± 1.4 fmol/mg protein). Basal platelet cyclic AMP levels (black subjects, 7.8 ± 1.1 pmol/mg protein; white subjects, 14.5 ± 2.4 pmol/mg protein; p < 0.05) and PGE2-induced increases in platelet cyclic AMP levels were higher in white subjects (black subjects, 47.1 t 3.3 pmol/mg protein; white subjects, 65.5 ± 3.4 pmol/mg protein; p < 0.001). Basal lymphocyte cyclic AMP levels (black subjects, 1.2 ± 0.3 pmol/106 cells; white subjects, 2.8 ± 0.6 pmol/106 cells;p < 0.05) and mean isoproterenol-induced cyclic AMP increases were also higher in white subjects (black subjects, 6.2 ± 0.6 pmol/106 cells; white subjects, 8.5 ± 0.8 pmol/106 cells; p < 0.05). Responses to isoproterenol as fold stimulation of basal were not significantly higher in black subjects (8.51 ± 0.97 versus 6.16 ± 0.86 fold-stimulation of basal). Platelet responses to PGE2 as fold stimulation of basal (black subjects, 7.9% ± 0.7%; white subjects, 8% ± 1.3%) and α2-receptor-mediated inhibition of PGE2 responses by UK-14304 (black subjects, 38.2% ± 1.7%; white subjects, 40.6% ± 2.3%) were also similar in the two groups. © 1990.